The invention relates generally to communication systems, and more particularly to communication systems which support wireless mobile telephones or other types of user terminals which include soft-labeled keys (SLKs).
Conventional communication systems may be configured to support wireless terminals which utilize SLKs. The functions associated with such keys can be varied under control of a system switch or switch adjunct, such that the same physical key can represent multiple features at different times. This compensates for the typical lack of user interface xe2x80x9creal estatexe2x80x9d on the wireless terminal by providing full feature access even with many fewer physical keys than, e.g., a corresponding wired terminal supported by the same system. A wireless terminal which incorporates SLKs generally includes a display containing the labels associated with the SLKs. In a conventional premises switching system, updates of these labels are typically explicitly controlled by the switch, e.g., based on predetermined functional modes associated with an operating context of the wireless terminal, and/or in response to commands entered by a user at the wireless terminal.
A significant problem with providing such a context-sensitive soft-labeled wireless terminal is that a number of run time misoperations or service degradations can occur if conventional command and update strategies are used to drive the wireless terminal. For example, if the system switch provides updates on a per-key-depression basis, the switch expends a considerable portion of its processing capacity in simply updating the label context of the SLKs on the wireless terminal. This is undesirable since it reduces system capacity, and since it introduces potentially unacceptable delays in updating the key labels. The latter difficulty may also lead to an interpretative misoperation. For example, assume the user depresses multiple SLKs at the wireless terminal. As a result, the switch sends a collection of updates to the terminal, and the first SLK update is processed and displayed. However, if the user then depresses another one of the SLKs, the switch has no way of knowing if all of the updates have been processed at the terminal, and therefore must impose interpretive assumptions about the terminal labels being displayed at the point in time when an SLK is depressed. This is an undesirable interpretive race condition, since the switch is mapping terminal button identifiers to system feature codes and the identifiers and codes may be desynchronized. Another problem associated with conventional control of SLKs is that a significant amount of bandwidth can be expended in the process of transmitting updates to the wireless terminal, thereby reducing the local radio access efficiency of the system.
Additional problems arise in conventional systems with regard to feature access control. The SLK display line in a terminal of such a system will generally present those features that are of the most use to the user in any given context. This in turn requires that the same area of the display present different features at different times, and in different contexts. For example, a terminal in an IDLE condition would have no use for a call management feature such as HOLD, while a feature such as a directory service would be of value. Therefore, the display must provide different SLK labels during different conditions. Also note that, depending on the service mode, the same system feature may be required in numerous contexts. For example, the HOLD feature may be of value during any incoming or outgoing call, and may also be of value during conferencing and transferring operations. This being the case, the HOLD feature will have four occurrences in a dynamically changing feature mix presented to the user via the SLKs. Conventional techniques are generally unable to provide efficient control of feature access. Such techniques may require an excessive number of multiple update transmissions from the serving switch to the terminal, thereby increasing the bandwidth required to support the terminal user interface.
A need therefore exists for techniques which allow a communication system switch to control SLKs of a wireless terminal user interface in a more efficient manner, while avoiding the run time misoperations and other problems associated with conventional techniques.
The invention provides feature access control in a terminal of a communication system by creating a bidirectional mapping between single switch-based features and multiple state-based appearances of those features on the terminal. In an illustrative embodiment of the invention, feature access control is provided for soft-labeled keys (SLKs) of a wireless terminal using a control table and a label table. The control table associates a different set of SLK label identifiers with each state in a set of states of the terminal. The label identifiers of the control table are used as pointers into the label table which specifies, for each of the label identifiers, a corresponding label for one of the SLKs. For example, the label table may specify, for each of the labels identified by a given one of the label identifiers, a character string corresponding to the label, a feature identifier associated with the label, and a presentation attribute. The control table and label table together implement the above-noted bidirectional mapping between single switch-based features and corresponding state-based multiple appearances of labels identifying those features on the terminal. The control table and label table may be downloaded into the terminal from a switch of the system. The labels of the SLKs may be updated by, e.g., transmitting to the terminal a state identifier, an identifier of a most-recently activated feature, and a presentation attribute for that feature. The feature access control may be implemented in a system which utilizes a downloadable state-based control model to control SLKs on the terminal.
The feature access control of the invention provides a number of advantages over conventional systems. For example, the invention in the illustrative embodiment provides a bidirectional mapping, i.e., a one-to-many and many-to-one mapping, between single instances of switch features being represented as multiple instances of terminal features. A single point of update is provided for all instances of a label string corresponding to a given switch feature which is accessed from multiple states in the terminal, and a single point of storage is provided for all SLK label character strings, such that each string is stored only once. The invention allows entire SLK display lines to be updated by transmitting simple pointers, rather than displayable text, such that bandwidth consumption is considerably reduced. These and other features and advantages of the present invention will become more apparent from the accompanying drawings and the following detailed description.